从推特中提取主题标签 - R 错误中的字符串

Question

我有推特数据。使用 library(stringr) 我已经提取了所有的网络链接。但是，当我尝试做同样的事情时，我遇到了错误。相同的代码在几天前就起作用了。以下是代码：

 library(stringr)
 hash <- "#[a-zA-Z0-9]{1, }"
 hashtag <- str_extract_all(travel$texts, hash)

错误如下：

 Error in stri_extract_all_regex(string, pattern, simplify = simplify,  : 
   Error in {min,max} interval. (U_REGEX_BAD_INTERVAL)

我已经重新安装了 stringr 包....但没有帮助。

我用于网页链接的代码是：

 pat1 <- "http://t.co/[a-zA-Z0-9]{1,}"
 twitlink <- str_extract_all(travel$texts, pat1)

可重现的例子如下：

 rtt <- structure(data.frame(texts = c("Review Anthem of the Seas Anthems      maiden voyage httptcoLPihj2sNEP #stevenewman", "#Job #Canada #Marlin Travel Agentagente de voyages Full Time in #St Catharines ON httptconMHNlDqv69", "Experience #Fiji amp #NewZealand like never before on a great 10night voyage 4033 pp departing Vancouver httptcolMvChSpaBT"), source = c("Twitter Web Client", "Catch a Job Canada", "Hootsuite"), tweet_time = c("2015-05-07 19:32:58", "2015-05-07 19:37:03", "2015-05-07 20:45:36")))

Answer 1

您的问题来自 hash:

中的空格

 #Not working (look the whitespace after the comma)
 str_extract_all(rtt$texts,"#[a-zA-Z0-9]{1, }")
 #working
 str_extract_all(rtt$texts,"#[a-zA-Z0-9]{1,}")

Answer 2

您可能需要考虑使用我为此任务维护的 qdapRegex 包。它使提取 url 和散列标签变得容易。 qdapRegex 是一个包含一堆罐装正则表达式的包，并使用令人惊叹的 stringi 包作为后端来执行正则表达式任务。

rtt <- structure(data.frame(texts = c("Review Anthem of the Seas Anthems      maiden voyage httptcoLPihj2sNEP #stevenewman", "#Job #Canada #Marlin Travel Agentagente de voyages Full Time in #St Catharines ON httptconMHNlDqv69", "Experience #Fiji amp #NewZealand like never before on a great 10night voyage 4033 pp departing Vancouver httptcolMvChSpaBT"), source = c("Twitter Web Client", "Catch a Job Canada", "Hootsuite"), tweet_time = c("2015-05-07 19:32:58", "2015-05-07 19:37:03", "2015-05-07 20:45:36")))

library(qdapRegex)
## first combine the built in url + twitter regexes into a function
rm_twitter_n_url <- rm_(pattern=pastex("@rm_twitter_url", "@rm_url"), extract=TRUE)
rm_twitter_n_url(rtt$texts)

rm_hash(rtt$texts, extract=TRUE)

给出以下输出：

## > rm_twitter_n_url(rtt$texts)
## [[1]]
## [1] "httptcoLPihj2sNEP"
## 
## [[2]]
## [1] "httptconMHNlDqv69"
## 
## [[3]]
## [1] "httptcolMvChSpaBT"


## > rm_hash(rtt$texts, extract=TRUE)
## [[1]]
## [1] "#stevenewman"
## 
## [[2]]
## [1] "#Job"    "#Canada" "#Marlin" "#St"    
## 
## [[3]]
## [1] "#Fiji"       "#NewZealand"

从推特中提取主题标签 - R 错误中的字符串

Extracting hashtags from twitter - string in R error

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